US 6992259 B1
A float switch made from plastic and impervious to corrosion, with improvements over the prior art including a more responsive operation resulting from use of a wide float switch body and a closely fitting housing that allow rapid shut-off of condensate production after collection of only a very small amount of fluid, a small housing dimension for easy installation in the small areas used for air conditioning system air handlers, a removable bottom cap for easy debris removal as well as float switch body adjustment for changing conditions, a housing design that allows operation without air vent holes in the housing, and anti-rotation features that stabilize the level orientation of the float switch body needed for proper operation after installation. By its quick and reliable response, the switch promotes use and longevity of energy efficient air conditioners without concern for the increased condensate produced, protecting the environment and energy resources.
1. A multi-purpose float switch assembly for use in association with an auxiliary fluid discharge line connected to a fluid producing system that also has a main fluid discharge line, to shut off the system when fluid flow in the auxiliary discharge line is impeded and poses a risk of the fluid in the main fluid discharge line backing up into the system and causing damage, said assembly comprising:
a housing having an open bottom end, an enlarged upper portion, an opening centrally through said top surface, and an extension outwardly depending from said housing with a widened upper end and distal end with a threaded configuration;
watertight closure means adapted for sealing said open bottom end of said housing;
a shaft with a threaded top portion positioned to extend through said central opening in said enlarged upper portion of said housing,
fastening means adapted for removably securing said shaft to said enlarged upper portion of said housing;
a float switch body concentric with said shaft and positioned for free movement along said shaft;
stop means adapted for removable attachment to said shaft in a position lower than the discharge line and maintaining said float switch body on said shaft by blocking downward movement of said float switch body beyond the position where said stop means is attached to said shaft; and
whereby the amount of upward vertical movement of said float switch body needed to activate a signal for shutting off the fluid producing system in fluid communication with said system is adjusted with said fastening means and said stop means so that when electrical wires are connected between said float switch body and the fluid producing system, and a predetermined level of fluid accumulates in said housing sufficient to elevate said float switch body and cause a signal to be sent via the electrical wires to the fluid producing system, the system is shut off and the risk of damage to the system from fluid back up is avoided.
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1. Field of the Invention
This invention relates to liquid-level float switches used for in-line and auxiliary applications, specifically to a float switch of sturdy construction that is primarily contemplated for use in condensate collection applications, but which is also useful in other fluid transport applications. The most preferred embodiment of the present invention is small and comprises a housing with a maximum height dimension of approximately two inches and a maximum width dimension of approximately three inches, including its connecting extension/arm that is used for fluid communication with a discharge line. Also in the present invention, an adjustable float switch body is positioned for vertical movement within the housing, guided by a concentrically positioned shaft that is secured to the enlarged upper portion of the housing with fastening means, such as but not limited to a lock-nut. The amount of float switch body displacement is preferably adjustable and defined by the positions of the lock-nut and a disk-shaped bottom stop when both are secured to the shaft. It is contemplated for both the lock-nut and stop to be removably connected to the shaft so that the float switch body can be removed when needed for maintenance, inspection, and replacement purposes. The float switch body has a large surface area for enhanced buoyancy and improved responsiveness during operation, with the housing closely positioned around the float switch body and having an open bottom end that is closed by a securely affixed cap or other closure that can be easily removed to check for debris in the main or auxiliary fluid line to which it is connected. Preferably, but not limited thereto, the bottom closure is threaded and attached with an o-ring to provide a leak-resistant connection. As the upper portion of the housing is enlarged, no air vent openings are required to prevent an airlock malfunction. Alignment guides are also preferably incorporated as a part of the extension/arm to assist in obtaining a level positioning of the housing during installation for unimpeded and proper float switch body operation, and maintaining the optimal orientation during long term operation. The alignment guides can have many configurations, such as but not limited to one or more of the following, ridges, notches, pointed teeth, square teeth, a scalloped pattern in combination with complementary pointed teeth, and/or any other configuration that incrementally provides a ratcheting type of engagement for alignment and level-preserving purposes. Electrical wires extending through the top of the housing provide the electrical connection needed between the rising float switch body and a fluid producing source, so that collection of a very small amount of water in the housing as a result of hindered or clogged fluid flow in the fluid discharge line to which the housing is connected, such as but not limited to 7.5 ml or 1.5 teaspoons, is able to activate the float switch body and promptly interrupt operation of the fluid producing source. The configuration of the present invention housing that allows positioning of the bottom of the float switch body lower than the discharge line of a fluid producing system, ensures that a very small amount of collected fluid will cause the termination of fluid production by the system. Since the float switch body does not remain in contact with condensate and added maintenance fluids, and only a small amount of collected condensate triggers the switch body, it remains responsive and functional, thereby causing the air conditioning coils to last longer for release of less ozone depleting chemicals annually into the environment. The responsiveness and reliable functionality of the present invention also promotes efficient operation of higher energy rated air conditioning systems that produce a significantly larger amount of condensate due to the present invention being able to terminate the production of condensate after only a very small amount of it is collected after a blockage occurs in the discharge line. In its basic configuration the present invention float switch is ready for auxiliary use, and with the use of one or more connecting accessories, it can be readily adapted for in-line use.
2. Description of the Related Art
When air conditioning condensate and other fluids travel in discharge lines, there is often a risk of overflow or back-up into the system producing it. As a result, liquid-level float switches have been employed in-line with such discharge lines, and also in an auxiliary capacity, to shut-off the source of fluid flow into the line when the amount of fluid therein exceeds a predetermined depth. However, currently known float switches are deficient in many ways and thereby subject to malfunction, less responsive operation, more costly installation, and/or unstable installation. Overflow and condensate back-up, particularly in older systems where back-up is repeatedly encountered, can lead to corrosion of air conditioning coils, causing freon and/or other ozone damaging chemicals to be lost to the atmosphere. Many prior art float switches tend to be at risk for malfunction since they are in constant contact with the fluid in the discharge line, and subject to impaired operation as a result of such things as rust, algae, mold, and/or other debris that grows or accumulates in the discharge line over time. Also, some prior art liquid-level float switches tend to have float switch bodies that wobble relative to the shaft with which they are associated, a condition that can lead to less responsive operation or malfunction that may worsen over time. In addition, some prior art float switches are at risk for premature malfunction as a result of being made from materials that are not completely corrosion-resistant. In contrast, the present invention is made from plastic that is impervious to corrosion. Also, its float switch body is wider than those of known prior art float switches for greater water displacement, however, its housing has a small width dimension for easy installation in the tight spaces in residential construction often permitted for air handler location and the connection of condensate discharge lines. In addition, the present invention uses less water to activate electrical shut-off for a faster response time than prior art devices as the bottom portion of its float switch body sits below the discharge line, the extension/arm of the present invention housing has a ratcheting-type leveling-assist feature for the float switch body to facilitate level installation and maintenance of the established optimum orientation during its operation, no holes are needed in the housing to prevent air-lock malfunction as its housing is configured with an enlarged upper surface or bubble that provides a continuous approximately three-fourths inch water passage throughout, the float switch body does not constantly sit in water where it could malfunction due to an accumulation of algae/rust/mold/debris over time, to provide a more secure installation than prior art devices its threaded connections comprise the standard fittings used in threaded pipe connections and not the coarse hose bib threads typically used in the majority of prior art devices, and its bottom cap or other bottom closure permits easy access to the float switch body and cleanout of algae/mold/rust/debris from the housing that could otherwise cause malfunction of the float switch body. In combination with connecting accessories, the housing can be used in a variety of auxiliary applications or be installed for in-line use. Since the present invention is small and has a simple design, it uses less materials for its construction and thereby is also cost effective to make and use. Within the next few years, higher rated air conditioning units will be required by law for fuel efficiency. The large coils used therein will create more condensate. Since condensate continues to drip for ten to fifteen minutes after the air conditioning unit has been shut off, it is very important for in-line and auxiliary switches to be responsive to very small amounts of water and be subject to minimal risk of malfunction, thus having a significant positive impact on the environment. The present invention is configured to be responsive to and meet the needs of the higher rated systems, as well as those of current systems. Without a responsive condensate/fluid flow shut-off switch, air conditioning systems with a higher energy rating would more quickly encounter overflow and back-up problems and their overall efficiency would be diminished. Therefore, in addition to having a significant positive impact on the environment, by promoting efficient use of the higher energy rated air conditioning systems, widespread use of the present invention will also have a significant impact on energy savings in the United States. No condensate/fluid flow shut-off switch is known with all of the features and advantages of the present invention.
Objectives and Advantages
The primary object of the present invention is to provide a multi-purpose float switch for auxiliary applications, which can also be adapted for in-line use, that is capable of activating an electrical signal for shutting off an associated fluid producing system when fluid flow in the main discharge line transporting fluid away from the system becomes significantly hindered or clogged and thereby poses a risk of fluid back-up into the system. A further object of this invention is to provide a float switch with a compact housing designed for prompt and cost effective installation in the close-fitting areas sometimes built to accommodate residential air conditioning air handlers, such as but not limited to air conditioning or maintenance closets that typically have a surplus space surrounding the air handler no greater that three or four inches on any one side. It is a further object of the present invention to provide a float switch that is sturdy in construction and designed for responsive and reliable operation. A further object of the present invention to provide a float switch that is capable of being securely installed in a level orientation for proper float switch body movement and will remain substantially in its optimal orientation during its entire period of use. Another object of the present invention is to provide a float switch with a float body having a bottom surface that is located in a position lower than the discharge line to which it is connected so that it will deploy to shut-off the associated fluid producing system when only a very small amount of fluid is collected in the housing surrounding it. It is an object of the present invention to provide a float switch that is protected against air-lock malfunction without the use of vent openings. A further object of this invention is to provide a float switch that is protected against malfunction from debris/mold/rust/algae in condensate/fluid discharge line. In addition, it is a further object of the present invention to provide a float switch that is made from corrosion-resistant materials that resist premature deterioration and malfunction. It is also an object of the present invention to provide a float switch that has cost-effective construction for widespread distribution and use. A further object of this invention is to provide a float switch that positively affects the environment and the conservation of energy resources by promoting air conditioner longevity and the efficient use of higher energy rated systems.
As described herein, properly manufactured and installed, the present invention would provide a float switch that is prepared for use in an auxiliary or dead end discharge line connected to a fluid producing system, such as but not limited to air conditioning systems, to promptly shut-off that system in response to only a small amount of the fluid being diverted from the system's main discharge line and into the auxiliary line as a result of fluid flow in the main discharge line becoming significantly hindered or clogged, such as with algae, mold, rust, and/or other debris, and failure of any switch device in the main discharge line to shut down the system and avert the fluid back-up damage thereto that would otherwise result if the system were allowed to continue its fluid production. In the alternative, in combination with one or more connecting accessories, the present invention float switch can also be used in an in-line connection with the main discharge line, or a variety of other auxiliary fluid flow applications. The most significant advantages provided by present invention are its design and sturdy construction for reliable performance in shutting off fluid production at the first signs of impaired fluid flow, when only a small amount of fluid (as low as approximately 7.5 mls) has been diverted into its housing. Such a capability will become increasingly important as more energy-efficient air conditioning systems, which generate more condensate than existing systems, are more commonly employed for residential and commercial use. The structure of the present invention housing and extension/arm causes the bottom of the float switch body inside its housing to be positioned lower than the discharge line to which it is connected, resulting in a capability for its float switch body to react to fluid flow impairment situations when only a small amount of fluid is diverted into the housing. No other switch for similar applications is known to have the same structure or capability. The most preferred embodiment of the present invention is small and comprises a housing with a maximum width dimension of approximately three inches, including its connecting extension member or arm. A float switch body is positioned for vertical movement within the housing, and guided in that movement by a concentrically positioned shaft that is secured to the top of the housing. The amount of float switch body displacement needed to active a shut-off signal to stop fluid production is defined by an upper lock-nut and a disk-shaped bottom stop that are both connected to the shaft and are adjusted according to need upon installation, which makes the present invention float switch readily adaptable to a wide variety of applications and changing needs by simple recalibration of the amount of float switch body displacement. The float switch body has a large surface area for enhanced buoyancy and improved responsiveness during operation, with the housing closely positioned around the float switch body and having an open bottom end that is closed by a securely affixed cap or other closure that can be easily removed and replaced during checks for debris/rust/algae/mold in the condensate/fluid discharge line to which it is connected. Preferably, but not limited thereto, the cap or other closure used has a threaded connection and is further secured in its leak-resistant connection with an o-ring. Although the cross-sectional configuration of the present invention housing and float switch body must complement one another to minimize the amount of collected fluid required for float switch activation, the actual configuration of both may be other than circular, and include but not be limited to an ellipse, square, hexagonal, octagonal, pentagonal, non-equilateral polygon, irregular polygon, and the like. A slight bubble or enlargement in the upper portion of the housing allows sufficient fluid/condensate flow to prevent air-lock malfunction without the need for air vent openings in the housing. The extension/arm in the most preferred embodiment of the present invention, which outwardly extends from the housing and is used for connection and fluid communication with a discharge line, also has a widened upper end to assist in preventing air-lock malfunction and further has ratchet-like alignment guides configured to assist an installer in obtaining a level positioning of the housing for proper float switch body operation. Electrical wires extending through the top of the at least partially hollow present invention shaft provide the electrical connection needed with the fluid producing system so that the signal activated by the rise of the float switch body in response to a predetermined amount of fluid collection in its surrounding housing can travel to the fluid producing system and promptly shut it off. The enlarged float switch body and close-fitting housing allow for the collection of a only very small amount of condensate/fluid, such as but not limited to 7.5 ml or 1.5 teaspoons, being required to cause deployment of the float switch body and interruption of condensate production. The present invention is typically made from plastic, and thereby impervious to corrosion, which in combination with its sturdy construction avoids premature deterioration and continued operation for an extended period of time.
Although the description herein provides preferred embodiments of the present invention, it should not be construed as limiting its scope. For example, variations in the height and diameter of the housing, bottom closure, float switch body, and shaft used; the size and number of threads used on the upper portion of the shaft for housing connection; the length of the extension/arm depending from the housing; the perimeter configuration and dimension of the lock-nut used to tighten the shaft to the housing; the perimeter configuration of the bottom cap or other closure relative to the housing; and the number and spacing of protrusions on the outside surface of the bottom cap or other closure used to facilitate hand manipulation during installation and removal of the closure, if any; in addition to those variations shown and described herein, may be incorporated into the present invention. Thus, the scope of the present invention should be determined by the appended claims and their legal equivalents, rather than being limited to the examples given.
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The materials from which the most preferred embodiment 2 is made can vary, but must be impervious to corrosion. Preferably for cost considerations, although not limited thereto, it is contemplated for housing 4, float switch body 28, stop 30, shaft 10, and lock-nuts 8 to all be made from plastic. Resistance to UV radiation is not necessarily a contemplated feature of the present invention, unless dictated by the application. Manufacture of the present invention could be accomplished by blow molding, injection molding, assembly of pre-formed individual components, or a combination thereof, with the choice of manufacturing being determined by the anticipated purchase cost to consumers and the expected duration of use without maintenance, parts replacement, or repair. Although size of the present invention is not critical, for many condensate collection applications, the length, width, and height dimensions of the combined housing 4, bottom cap 6, and extension 36 would be less than three inches.
Prior to use of the most preferred embodiment of the present invention in an auxiliary installation, float switch body 28 would be positioned on shaft 10 so that electrical wires (not shown) extend upwardly beyond its threaded top end 10. Preferably, the upper threaded end 10 of shaft 26 would then be inserted through the central opening 32 through the enlarged upper surface 22 of housing 4 with the two lock-nuts 8 so that the remainder of shaft 26 is vertically extending through housing 4 with float switch body 28 substantially filling the interior space within housing 4. Washers 24 can also be used in association with lock-nuts 8. Stop 30 would be fixed to the bottom portion of shaft 26 to adjustably define the lower boundary of float switch body 28 displacement vertically along shaft 26 during use, with adjustment further being possible through the repositioning of lock-nuts 8. The adjustment and positioning of float switch body 28 would be governed by the application and the depth of fluid needed to cause float switch body 28 to rise and send a signal to the system producing the fluid so as to cause termination of fluid flow through the main discharge line, as well as the auxiliary line to which housing 4 is connected. To facilitate installation of housing 4 in a usable position, it is contemplated that sleeve 16 would first be attached to extension/arm 36. Thus, it is contemplated that all an operator/installer would have to do is connect an appropriate connecting accessory 18, 58, 60, 50 with an end cap 62, and/or other connecting accessory, to the auxiliary condensate discharge line, and then connect the distal end of extension/arm 36 with the assistance of sleeve 16 to the end of connecting accessory 18 and/or other accessory having a threaded configuration 20. Once housing 4 is in a secured and usable position, the installer or operator would check it for the stable and level positioning required for reliable and uninhibited vertical movement of float switch body 28. Leveling ridges 34 could be used to incrementally rotate housing 4 until shaft 26 is in a sufficiently vertical position so that float switch body 28 moves freely using shaft 26 as a guide for its up and down movement. It is important to note that in the absence of water or other fluid in housing 4, float switch body 28 is located in a position below the bottom of the discharge line, so that only a very small amount of condensate or other fluid is needed to activate it and cause it to rise to the level needed to terminate fluid production. The electrical wires (not shown) extending from the threaded top portion 10 of shaft 26 would then be connected to the system providing water, condensate or other fluid traveling through the discharge line in fluid communication with housing 4. Then, when fluid flow in the discharge line (not shown) to which housing 4 is connected becomes impeded and water or other fluid in housing 4 exceeds a predetermined level that indicates a risk of fluid back-up into the system generating the fluid as a by-product of its operation, the rising water will cause float switch body 28 to also rise and send a signal to shut off the fluid generating system. Airlock within housing 4 that could potentially interfere with the proper vertical movement of float switch body 28, is prevented by the enlarged upper portion 22 of housing 4. Minimal maintenance is contemplated. If housing 4 is made from translucent, transparent, or partially transparent materials, an operator could visibly assess the effective operation of float switch body 28 without removing it from housing 4 or separating bottom cap 6 from housing 4. The size and configuration of housing 4 connecting accessories 18, 50, 58, and 60 are not critical and can vary depending upon design and price point considerations, such as but not limited to ease of manufacture, the desirability of connection to standard connectors and fittings, and effectiveness of operation. It is further contemplated for housing 4 to have a compact design and construction for efficient packaging and transport, in addition to use in small spaces. For in-line applications, housing 4 can be secured to the housing connection arm 56 of a connecting accessory 50, the tubular configuration 52 of which has its opposed end openings 66 in fluid communication upstream and downstream with a discharge line (not shown). Connecting accessory 50 could first be connected to housing 4, then to the discharge line, or vice versa. Leveling ridges 34 on the housing connection arm 56 of a connecting accessory 50 mate with the leveling ridges 34 on extension/arm 36 to aide in the incremental positioning of housing 4 in a level orientation for proper and unimpeded movement of float switch body 28 relative to shaft 26. As with its auxiliary applications, housing 4 is positioned relative to the discharge line/pipe/conduit (not shown) so that the bottom portion of float switch body 26 is in a position lower than the bottom of the discharge pipe/conduit connected in-line with it, and the accumulation of fluid needed to cause float switch body 26 to rise and shut off the system producing fluid can be very small. The wall 54 between tubular configuration 52 and housing connection arm 56 prevents the routine flow of fluid in the discharge line/pipe/conduit from coming into contact with float switch body 26. This prevents a risk of float switch body 26 malfunction when needed, as a result of a fluid-caused deterioration of float switch body 26, or as a result of the gradual build up of algae, mold, rust, and/or other debris in the fluid traveling through the line/pipe/conduit in fluid communication with housing 4. The height of wall 54 can be manufactured according to the needs of an intended application. Further, angled clean out 68 can be used in both in-line and auxiliary applications. Thus, if an air conditioning or other condensate/fluid producing system has a main discharge line and an auxiliary line, two angled clean outs 68 can be used, one for each line. Typically, although not limited thereto, it is contemplated for angled clean outs 68 connected in in-line applications to be connected upstream from housing 4.